Substrate processing apparatuses are being widely used to process substrates, for example, to form thin films on a surface of a substrate. In order to process a plurality of substrates within a short period of time, a substrate processing apparatus that is provided with a plurality of substrates in a processing chamber and processes the plurality of substrates has been suggested. A robot arm capable of conveying the substrates into the processing chamber may be provided in order to arrange the plurality of substrates on stations, and it takes a lot of time period to load/unload the substrates. Therefore, there is a demand for an apparatus capable of loading/unloading the substrates rapidly for improving productivity.